Inline valve for permanent central heating drain?

Hi, any recommendations for an in-line valve for a permanent central heating drain point?

I Probably needs to be pretty low down (between horizontal return pipe and floor?), so cant be anything big or bulky.

I also need to attach the pressure relief drain-off to the downstream part of this same drain. Will be using 15mm copper.

ian

iwilson16 said:

I also need to attach the pressure relief drain-off to the downstream part of this same drain. Will be using 15mm copper.
ian

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Hi Ian,

Not sure what you mean by this? You’re asking for a drain off, but then part of the same drain? Are you on about 2 different things?

Instead of a little drain cock thing that you attach a hose to, I want a permanent drain valve. I’m in a first floor flat, so running a hose to the outside is not an option. Instead, i want to connect it to the pressure relief pipe, downstream of tundish, which then runs into the main soil stack 10m away. (I plan to replace tundish with a hotun).

currently the CH drain flows through an old pipe at the rear, and empties onto downstairs neighbours back step!! I don’t have access to the under-floor where this pipe runs, nor to the rear of the property.

I’m running a new pipe to the soil stack at front of the property. I have a ground floor store room below a bathroom. The soil stack runs down the inside corner of these rooms, so I can run the pipe at a gradient through the store room to the soil stack. I’m the only property using this soil stack. It services 2 bathroom on 1st and 2nd floors (Victorian townhouse conversion).

Or inline washing machine valve and a 15mm x 3/4 female compression elbow.

So I've been looking more closely at what I have currently. The history of this flat (split level, 3 dbl bed, 2 bathrooms) is that when I bought it in 2015 it had a vented gravity fed HW system, 150 litre HW cylinder, and a relatively new Bosch Greenstar 30 boiler. The HW pressure was rubbish, unsurprisingly - just 2m of head in one bathroom and 5m in the other bathroom and kitchen.

I had the system replaced with an unvented one, 170 litre Sapphire SS HW cylinder, and a bunch of new radiators. The plumber just connected the drain-off from the pressure relief of the HW cylinder into an existing drain point of the old system. This was approx 2m of 22mm pipe and then 4m of 15mm pipe. Now having skimmed the Sapphire tech data I'm having doubts this is sufficient. It talks a lot about pipe diameter, length, and number of bends. If I re-route it to the other side of the property then it definitely wont meet regs if 15mm is used .... that would be about 10-12m away with a few bends. 22mm might not even be enough.

UV discharge pipework is a completely different matter. Get a G3 registered person to alter any such components of the install.